Field of Disclosure
The present disclosure concerns a rotatable arrangement for a gas turbine engine and/or a gas turbine engine.
Description of the Related Art
Gas turbine engines are typically employed to power aircraft. Typically a gas turbine engine will comprise an axial fan driven by an engine core. The engine core is generally made up of one or more turbines which drive respective compressors via coaxial shafts. The fan is usually driven off an additional lower pressure turbine in the engine core.
A fan generally includes a hub having a plurality of blades extending therefrom. Referring to FIGS. 1 and 2, annulus fillers 126 are provided between adjacent blades 124 to provide an optimal gas washed surface between the blades. A pressure side seal 128 extends along the pressure side of the blade at the interface between an annulus filler and the blade, and a suction side seal 130 extends along the suction side of the blade at the interface between another annulus filler and the blade. A gap 132 is formed at the trailing edge 134 of the blade between two adjacent annulus fillers 126.
The principle flow of air through the fan is indicated by arrows A in FIGS. 1 and 2. The flow is generally axial from a leading edge 136 to a trailing edge 134 of the blades 124. However, due to the gap 132 at the trailing edge, some of the air is recirculated around the trailing edge back along the suction side of the blade, as indicated by arrow Ar1. This recirculated air then re-enters the air flow A approximately mid-way along the chord of the blade (indicated by arrows Ar2).
This recirculation of air introduces losses into the air flow A and therefore reduces fan root efficiency.